.flex-basic(@justify-content: flex-start, @align-items: stretch) {
  display: flex;
  justify-content: @justify-content;
  align-items: @align-items;
}
.flex-center() {
  .flex-basic(center, center);
}
.flex-horizontal(@justify-content: flex-start, @align-items: stretch) {
  .flex-basic(@justify-content, @align-items);
}
.flex-vertical(@justify-content: flex-start, @align-items: stretch) {
  .flex-basic(@justify-content, @align-items);
  flex-direction: column;
}
